This is really splitting hairs. The base of the tongue is located in the oropharynx and forms the anterior wall of it. The tonsillar fossa, etc. forms the lateral walls on each side, the superior aspect of it is formed by the inferior surface of the soft palate ..... and so on. I have always heard this referred to as the space that is surrounded by these structures, and the structures are named to give you some parameters of where the space is. I guess technically (using a gross generalization) if a room is defined by its walls, than those walls are part of the room even if one of them is also part of a hallway that is not actually part of the room itself. Since the question was is the tongue part of it, I said no, because the most of the tongue is not part of the oropharynx, it is located directly in the oral cavity, not any part of the pharynx, and a unique anatomical structure unto itself.

But one thing is clear, you guys here are getting pretty damn well educated and smart, and I better be careful not to give half answers in the future..... JeffL is now the official anatomical question answerer on the boards, since he called me on this with a reply that exceeded my generalization.